Enantioselective Organocatalytic Cyclopropanations. The Identification of a New Class of Iminium Catalyst Based upon Directed Electrostatic Activation

A new method for enantioselective organocatalytic cyclopropanation is described. This study outlines the identification of a new class of iminium catalyst based on the concept of directed electrostatic activation (DEA). This novel organocatalytic mechanism exploits dual activation of ylide and enal substrates through a proposed electrostatic activation and stereodirected protocol. Formation of trisubstituted cyclopropanes with high levels of enantio- and diastereoinduction is accomplished for a variety of α,β-unsaturated aldehydes and sulfonium ylides. In addition, mechanistic studies have found that this cyclopropanation reaction exhibits enantioselectivity and reactivity profiles that are in accord with the proposed DEA step

Discovery of Phosphodiesterase 10A (PDE10A) PET Tracer AMG 580 to Support Clinical Studies

We report the discovery of PDE10A PET tracer AMG 580 developed to support proof of concept studies with PDE10A inhibitors in the clinic. To find a tracer with higher binding potential (BP_ND) in NHP than our previously reported tracer <b>1</b>, we implemented a surface plasmon resonance assay to measure the binding off-rate to identify candidates with slower washout rate in vivo. Five candidates (<b>2</b>–<b>6</b>) from two structurally distinct scaffolds were identified that possessed both the in vitro characteristics that would favor central penetration and the structural features necessary for PET isotope radiolabeling. Two cinnolines (<b>2</b>, <b>3</b>) and one keto-benzimidazole (<b>5</b>) exhibited PDE10A target specificity and brain uptake comparable to or better than <b>1</b> in the in vivo LC–MS/MS kinetics distribution study in SD rats. In NHP PET imaging study, [¹⁸F]-<b>5</b> produced a significantly improved BP_ND of 3.1 and was nominated as PDE10A PET tracer clinical candidate for further studies

Small Molecule Disruptors of the Glucokinase–Glucokinase Regulatory Protein Interaction: 3. Structure–Activity Relationships within the Aryl Carbinol Region of the <i>N</i>‑Arylsulfonamido‑<i>N</i>′‑arylpiperazine Series

We have recently reported a novel approach to increase cytosolic glucokinase (GK) levels through the binding of a small molecule to its endogenous inhibitor, glucokinase regulatory protein (GKRP). These initial investigations culminated in the identification of 2-(4-((2<i>S</i>)-4-((6-amino-3-pyridinyl)­sulfonyl)-2-(1-propyn-1-yl)-1-piperazinyl)­phenyl)-1,1,1,3,3,3-hexafluoro-2-propanol (<b>1</b>, AMG-3969), a compound that effectively enhanced GK translocation and reduced blood glucose levels in diabetic animals. Herein we report the results of our expanded SAR investigations that focused on modifications to the aryl carbinol group of this series. Guided by the X-ray cocrystal structure of compound <b>1</b> bound to hGKRP, we identified several potent GK–GKRP disruptors bearing a diverse set of functionalities in the aryl carbinol region. Among them, sulfoximine and pyridinyl derivatives <b>24</b> and <b>29</b> possessed excellent potency as well as favorable PK properties. When dosed orally in <i>db</i>/<i>db</i> mice, both compounds significantly lowered fed blood glucose levels (up to 58%)

Discovery of Clinical Candidate 1‑(4-(3-(4-(1<i>H</i>‑Benzo[<i>d</i>]imidazole-2-carbonyl)phenoxy)pyrazin-2-yl)piperidin-1-yl)ethanone (AMG 579), A Potent, Selective, and Efficacious Inhibitor of Phosphodiesterase 10A (PDE10A)

We report the identification of a PDE10A clinical candidate by optimizing potency and in vivo efficacy of promising keto-benzimidazole leads <b>1</b> and <b>2</b>. Significant increase in biochemical potency was observed when the saturated rings on morpholine <b>1</b> and <i>N</i>-acetyl piperazine <b>2</b> were changed by a single atom to tetrahydropyran <b>3</b> and <i>N</i>-acetyl piperidine <b>5</b>. A second single atom modification from pyrazines <b>3</b> and <b>5</b> to pyridines <b>4</b> and <b>6</b> improved the inhibitory activity of <b>4</b> but not <b>6</b>. In the in vivo LC–MS/MS target occupancy (TO) study at 10 mg/kg, <b>3</b>, <b>5</b>, and <b>6</b> achieved 86–91% occupancy of PDE10A in the brain. Furthermore, both CNS TO and efficacy in PCP-LMA behavioral model were observed in a dose dependent manner. With superior in vivo TO, in vivo efficacy and in vivo PK profiles in multiple preclinical species, compound <b>5</b> (AMG 579) was advanced as our PDE10A clinical candidate